The present invention relates to a power hand tool adapted for cutting the packing frame of a glass panel, for example, a windshield packing frame and, more particularly, to a pneumatic power cutting tool with double-eccentric transmission shaft, which produces less vibration and noise during its operation.
When replacing the windshield glass of a motor vehicle or the glass panel of a big window, a cutting tool is used to cut the packing frame, which is fastened to the periphery of the glass by silicon rubber. It takes much time and labor to cut the packing frame with a hand-operated cutting tool. However, when a pneumatic power cutting tool is used to cut the packing frame, high noise and severe vibration are produced during the reciprocating motion of the cutting blade of the pneumatic power cutting tool, and the motor becomes overheat after a certain length of time in operation. The severe vibration of the pneumatic power cutting tool may injure the operator""s hands easily.
The present invention has been accomplished under the circumstances in view. It is the main object of the present invention to provide a pneumatic power cutting tool, which produces less vibration and noise during its operation. It is another object of the present invention to provide a pneumatic power cutting tool, which is convenient in use and practical for a long time operation without hurting the user""s hands. It is still another object of the present invention to provide a pneumatic power cutting tool, which is durable in use. To achieve these and other objects of the present invention the pneumatic power cutting tool comprises an eccentric shaft, the eccentric transmission shaft having a first eccentric shaft and a second eccentric shaft eccentrically forwardly extended from the first eccentric shaft, and adapted for reciprocating a cutter blade to cut the workpiece, a sliding block coupled to the first eccentric shaft by coupling means and adapted for sliding in a longitudinal sliding way in reverse to the reciprocation of the cutter blade to balance the centrifugal force due to the reciprocating motion of the cutter blade with the second eccentric shaft and to reduce the production of vibration and noise.